To answer this question we need to do a punnet square of an heterozygous cross, which is as follows:
P: Aa x Aa
Punnet square
[tex]\begin{bmatrix}{\placeholder{⬚}} & {A} & {a} \\ {A} & {AA} & {Aa} \\ {a} & {Aa} & {aa}\end{bmatrix}[/tex]As we can see we have 25% homozygous dominant, 25% homozygous recessive and 50% heterozygous, therefore the proportion of dominant homozygous is 25%
